Epidermolysis Bullosa

What is Epidermolysis Bullosa and what does it mean?
How common is EB?
What causes the disease and what does it do?
Forms and Symptoms
Treatments
Is EB deadly?
Is there a cure?
Is EB contagious?

What is Epidermolysis Bullosa and what does it mean?

Epidermolysis Bullosa, or EB for short, is the name given to a group of rare genetic skin disorders.

The skin is made up of many layers. The outer layer is called the epidermis while the inner layers are called the dermis. Bullosa means blister and lysis mean breakdown. Therefore Epidermolysis Bullosa means the breakdown and blistering of the skin.

How common is EB?

It is estimated that two in every 100,000 Americans, mostly children, have some form of EB.

What causes the disease and what does it do?

All forms of hereditary Epidermolysis Bullosa are caused by structural abnormalities in the skin. They are either abnormal, greatly reduced or absent. In most forms of EB the abnormality is in a molecule called keratin. The abnormalities of these proteins cause weakness in the cells. The most severe forms of Junctional EB are usually associated with defects in a molecule called laminin 5. The dystrophic forms, both recessive and dominant are usually due to defects in a molecule of the upper dermis called collagen VII. This molecule forms a structure called anchoring fibrils, which are responsible for keeping the epidermis firmly attached to the dermis.

Any part of the body containing collagen VII can therefore be effected, including the skin, eyes, mouth, teeth, esophagus, and gastrointestinal tract. Below is a diagram of the skin and where each form of EB effects.

Recessive Dystrophic EB, or RDEB, is inherited from both parents. They both are healthy carriers of the gene for RDEB. They then have a 25% chance of having a child with the disorder, a 50% chance of having a child that is a healthy carrier, and a 25% chance of having a child that is a healthy non-carrier. Because RDEB is recessive, both carriers must pass along their recessive gene, otherwise the dominant gene will take over resulting in a healthy child. Some forms of EB however are "spontaneous mutations" meaning they are not inherited.

Forms and Symptoms:

There are over 25 known forms of EB and they are split into three categories: Simplex, Junctional and Dystrophic. The severity has a wide range. One form goes away after one year of age. Others cause death at birth. Some only effect the hands and feet while others need bandaging due to the constant blisters and sores.

RDEB is considered one of the most severe forms. The structural weakness in the skin is in a deeper layer resulting in deep sores and extreme scarring. The skin is so fragile it can blister or sluff off from slight friction resulting in large blisters and sores all over the body. The blisters need to be cut and drained or else they continue to grow. The sores need antibiotics and constant bandaging. Most RDEB patients are practically bandaged head to toes. Many need wheelchairs because walking is too painful. This is also true with many of the Simplex varieties of EB because they effect the feet so greatly.

When most people hear the word blister, they think they know what it's like to have EB; however EB blisters are generally much much larger and often times much more painful. In severe cases the wounds can become extremely large. The scarring is similar to that of a burn victim. Blisters can arise from everyday actions such as scratching an itch, friction from clothing, wearing glasses, or bumping into someone.

Other symptoms of RDEB include:

Severe scarring causing the fingers to fuse to the palm in the shape of a fist. This is called "webbing." This also effects feet and toes often. Webbing can even cause the feet and hands to fuse into a bent position and the inability to stretch the legs and arms completely. Scarring in the esophagus causes it to become very narrow. This is due to the fact that scar tissue does not grow like normal skin. The fingers and toes get trapped into the skin, causing them to curl. In the esophagus the scar tissue keeps building up creating strictures (narrow areas in the esophagus)
Permanent loss of finger and toe nails at a young age
Severe Itching. When sores heal they tend to itch more. They also itch more if they are infected. With so many sores constantly trying to heal it causes constant itches and tingles. Scratching, of course, causes a lot more damage to the skin. The itching can be more uncomfortable than the pain.
Malnutrition. This is caused because of iron-deficiency anemia, and also because many of the nutrients taken into the body go toward healing the many open wounds and disrupt the growth of organs. It is also hard to eat due to blistering in the esophagus and mouth. This means only soft foods can be eaten. RDEB patients often "choke" because food gets easily caught in their throat.
Severe problems with teeth, including severe tooth decay. Oral hygiene in severe forms of EB can be very difficult. Dentures are not an option due to the fragility of the gums.
Blisters in the eyes and Corneal Abrasions can be extremely painful. Eyes do dry out and get scratched very easily.
Anemia. Often times RDEB patients are iron deficient.
Squamous Cell Carcinoma, a skin cancer that is fairly common in RDEB patients over the age of 20. If caught early, this cancer can be removed fairly easily, however there are no big signs to warn you. Unfortunately this is what takes many of the lives of RDEB patients.

Treatments:

Some treatments, besides the obvious daily wound care and bandaging include:

A high protein, high calorie diet and possibly pureed diet
Hand and feet operations to release the webbing
Biopsies and removal of skin cancers
Esophageal transplant
Esophageal dilation
Oral surgeries
Iron supplements or transfusions
Blood transfusions
Epo shots (Procrit)
Periodic antibiotics to fight infection
G-tube placement
Lots of hope and laughter!

Is EB deadly?

There are currently only two types of EB that are considered lethal. The first is Junctional Herlitz, which is often deadly to newborns. Junctional Herlitz effects internally, including the airway causing major complications. The other form is RDEB-HS. Most with RDEB-HS do not live past their 30's due to severe malnutrition and a skin cancer called Squamous Cell Carcinoma. There are also other forms that can be very severe at birth, and can get slightly better with age.

RDEB is considered to get worse with age however, due to the constant breakdown of the skin and severe scarring.

Can EB be Cured or Treated?

Gene therapy is the only way EB can be cured. In 1993 the gene that causes Dystrophic EB was located. That was the first major step. More advances are being made every year giving much hope for the future. Although science is unpredictable and finding a cure for EB will be no easy task. There are currently a few creams and skin graphs being used to help treat chronic areas of the skin that keep breaking down. These include:

These however do NOT cure the skin in any way. The skin graphs are used to help speed along the healing process of sores that could otherwise take months are even years to heal. The EB genes take over the skin graphs making them as fragile as the rest of the skin.

Is EB contagious?

No, EB is not contagious. It is a genetic condition.

Source: Christina's Website

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